瓮安生物群中后生动物化石研究进展及问题讨论

Progresses and Questions on Studying Metazoan Fossils of the Weng'an Biota

贵州瓮安埃迪卡拉(震旦)纪陡山沱期磷酸盐化生物群具有生物多样性特征,包含有蓝菌、多细胞藻类、疑源类、后生动物休眠卵及胚胎、可疑的海绵动物、管状后生动物和微小两侧对称的后生动物等化石类型,是迄今为止全球保存最为完好的晚前寒武纪磷质化石库。瓮安陡山沱组磷质岩提供了早期生命从简单到复杂进化过程中的重要化石记录,展示了埃迪卡拉生物群出现以前早期多细胞生物的生命景观,为研究晚前寒武纪生物圈面貌提供了一个重要的埋葬学窗口。近来,通过醋酸浸解法,在贵州瓮安陡山沱期含磷地层中发现了大量疑似后生动物的实体化石(包含了所有已经报道的类型或与之相似的化石类型)新材料,为了解这些化石的内部构造特征,将一些化石包埋后制作了定向薄片。基于上述化石新材料,结合定向薄片的研究和前人的研究成果,本文详细介绍了瓮安生物群中后生动物化石研究的新进展和存在的问题。

The phosphatized biota of Ediacaran（Sinian） Doushantuo stage from Weng＇an, Guizhou, which constitute an exceptionally well-preserved phosphatized Lagerstaten of late Precambrian, consists of cyanobacteria, multicellular algae, acritarchs, rest eggs and embryos, questionable sponges, tubular animal and small bilaterian fossils. The phosphorites from Doushantuo Formation at Weng＇an, which contain important fossils of life evolution from simple to complex during late Precambrian and represent life scenery of early Ediacaran biota, provide an important taphonomic window for us to understand the biosphere of late Precambrian. Recently, a great lot of new data of the questionable metazoan body fossils （including all types or similar types of reported metazoan fossils） were found from Doushantuo phosphorites at Weng＇an, Guizhou. Conjunction with having been seen in SEM, furthermore, we imbedded a number of spheroidal and tubular fossils in epoxy resin and then thin sectioned them in controlled orientation. Based on the results of SEM and transmitted-light microscopy and the previous achievements in the study of the Weng＇an biota, the research evolvement and perspective of Weng＇an biota are introduced detailedly in this paper.